Repair, rebuild or recover your seat at home!

[cave weta]

A few weeks ago I bought a classic bike that needed a few jobs done to it.



Number one job was a full rebuild of the seat. As you see from the first photo, The seat had been seriously mucked about with . The previous owner was a short person who didn't know that the rear suspension height was adjustable! He had carved into the seat foam and removed 40 mm then attempted to recover this dogs breakfast that he had created with duvet filling and a cover made from prostitutes mini skirt vinyl !

[cave weta]

The previous dude did what he was capable of....


Over the next few posts I will explain how you can achieve professional looking results on your seat at home.

[cave weta]

Right-
Tools for the job
a blunt butter knife.
Side cutter pliers.
Staple gun that fires 6mm staples – no longer , no shorter. Ask a builder-
they use them for fixing building paper
Electric carving knife- pure luxury if you have one but a really sharp long knife will do the job well. By sharp – I mean fucking sharp!
Felt pen and ruler for marking out
angle grinder with 60 grit flexible disc. The disc needs to be for the next size up grinder because you need extreme speed so that the grinder wont dig in and tear the foam.
So if you have a 4” grinder – you use a 6” disc. Get it?

:EDIT: AlanB has a reall good improvement on this... 60 grit on a orbital is just as efficient - better surface finish- way safer!

[cave weta]

First step is removing the old cover. this is easily done with a bread and butter knife and small pliers to remove all the staples under the edge. Take note that the cover is stapled virtually continuously all the way around.
You will be doing this again when you fit your new cover.

Right – put the old cover to one side if you are going to keep the seat in its standard shape.- you will use it as a pattern later.

Turning to the foam now,- if you are just repairing the foam from sun cracking, water damage or accident damage you will need some foam from a car seat. The car wrecker/ breakers yard has loads of this that they are not allowed to burn so they will be pleased to give you as much as you need.

[cave weta]

If you are reshaping or adding to the thickness of your seat you can use the same stuff , but I prefer to go to PARA and buy a slab of the correct thickness and grade of foam.. You want the firmest stuff they have for seating. (the light green stuff.)

From Para – you can also buy 3M spray contact adhesive. You need a can of that too.

[cave weta]

OK- for simple cuts, tears and abrasions use your carving knife and the breadboard to cut the foam on to create the perfect 3D jigsaw piece to fill the hole and then spray both the seat and the new piece with contact adhesive – wait 10 mins and press them together.
After ½ an hour you can then trim the repair back to shape with the carving knife and for a perfect finish – use the grinder to blend it to the finished shape.




For re-modeling the shape and adding to the thickness of the seat.
Start by slicing the shaped base layer off the squab and then use that as your foundation to build on. It has all the fancy shaping that keeps your seat feeling like and looking like factory. Note the recess for the rear guard and maybe even the battery.

Now apply spray adhesive to both the base layer and your new foam block and wait 10 minutes.
Now join the two together and you can start marking your new profile or copy your old one .
Then the cutting, if you are the primo steady handed tradesman then just cut to the line. Making sure that you cut the whole way through in one cut .Not a little nibble from each side or you will end up with a nasty mountain range of daggs in the middle! But if you are not so confident. Cut 5mm outside your lines.
finish with the high speed grinder. The grinder will want to dig in so take very light strokes toward you only- if you push away from your body it will tend to dig in.

[cave weta]

Using the grinder is An OSH inspectors nightmare! You have to take the guard off so that the over size disc will fit. The disc will now come part way up the handle and want to eat your knuckles. The spindle hole in the disc is probably now the next size up from the mandrel so the disc can (if care is not taken) slip from eccentricity and vibrate madly. You must wear a dust mask, goggles, ear muffs and leather gloves. If you are a Harley owner,You will have your arseless chaps- so should use them too. ( sorry West Coast Choppers Inc but you deserve it!)

Sweet- so you have made it through the dangers of re foaming seats.


Next we will re make the seat cover.

[Madness]

The spindle hole in the disc is probably now the next size up from the mandrel so the disc can (if care is not taken) slip from eccentricity and vibrate madly.

This would usually only apply when using a 4" (100mm) grinder. They have a 5/8" (16mm) spindle, all the others from 4-1/2" (115mm) up have a 7/8" (22mm) spindle.

It would be very important to centre an over-sized fibre disc. At 16,000 odd rpm a fibre disc could fly apart & would hurt if it hit ya at that speed.

I've seen dickheads run 14" (350mm) cut-off wheels on a 5" (125mm) grinder. The wheel tends to scrape yer knuckles if you're not careful how you hold the grinder.

[AllanB]

A good post.
A orbital sander with a 60 grit pad also works well on the foam. Makes a mess of your shed though!

[cave weta]

Next we will re make the seat cover.

You can change the colour, add co loured accent panels, decorative stitching.
If you have re- shaped your foam to provide a hi and lo seat then check out how other seats of this design are cut and sewn – you may have to sew as many as 7 panels to make your cover. Some seats are able to be covered with one piece of vinyl and a hair dryer.

First you will be making a pattern. Use light card or
cheap warehouse supercheap tarpaulin material.

Newspaper is too light.
Make patterns for both sides as your work may not be quite symmetrical. Mark them left and right.
Make a pattern for the top and each side and mark the good side so that R is right and L is left. Make the patterns exact size.

Selecting the cover material:
Dont be tempted to use leather – it stretches when wet. Many types of vinyl are available. I use automotive vinyl for most seats and marine vinyl for older classic bikes as it is heavier and matches the old look. The automotive vinyl will stretch well in the sun or with a heat gun or hair dryer. Many bikes seats can be covered in one piece just like original with this. Gripper seats can be made easily too, and for no extra. The vinyl is just a heavily textured version used on some boat seats and jet skis.

[cave weta]

Transfer your shapes to your vinyl.

Now cut around the edge leaving 10mm extra as a seam allowance.
Most modern domestic sewing machines will handle two layers of vinyl, they will handle up to six layers for the corner joins and seams if the owner is not watching!

Use a pure polyester thread metric 20 0r 25 at least -not cotton. Cotton has no UV rating and will fall apart after a year or so.
Make little datum marks for you to follow when lining up the pieces, this way when you have it all sewn together and turned it out the right way, the corners will be in the same place on both sides and not 10mm out!!

Some bike seats are double stitched or top stitched which is way more durable. To do this, just stitch your panels together then turn it all out the right way and fold the little 10mm flap on the underside toward the top part of the seat. sew again 3mm to the top side of your first seam

[cave weta]

A good post.
A orbital sander with a 60 grit pad also works well on the foam. Makes a mess of your shed though!

hey that is an awesome trick!! I just tried it and no more skinned knuckles
and a way more controlable

[skidMark]

**waits for info on how to staple and stretch cover on the best**

[cave weta]

Patience grasshopper....

we will be doing that next.

[skidMark]

Patience grasshopper....

we will be doing that next.

__________________